Havent read all the thread, but grew up in a vaquero tradition (and show the top western eq horses in the country). It was progressive from hackamore (or muesero/no serrated serrate) to snaffle to spade. The horses were very much like working equitation horses, collected/ready to move and cut. They were upright/in front of the vertical rather than low necks and 'breaking at the poll' (the poll is the occipital lobe...so a horse does not flex there. They should lift and arc their neck and have a shortened base of support, not flex in the front part of their neck which straightens the hind legs).
It is a methodical tradition, and by the time the horse is in a spade/curb they should be a whisper of neck rein (certainly NEVER two hands on it). NO excessive bending of the neck (from the withers to head) which is often shown by NH. That excessive bending (especially low and closed) puts great pain on the bars, and is a clumsy excuse for control only. It controls the mind through pain and merely poses the horse (in what has become an acceptable western pleasure outline with the neck lower than withers).
Interestingly enough this 'old school approach' is also one which follows from france's dressage heritage. Caveson to snaffle to full bridle (or curb alone). What it does take is knowledge about the figures ridden, preserving the gaits of the horse, and perfected equitation and timing (not the chair seats of many of the pix here). Mho.